Microbial growth is a problem in many different places such as hospitals, slaughter houses, chicken farms, dairy farms and factories. Microbes can contaminate solid waste, water, fuel, petrochemical products and industrial fluids. Microbial presence and their metabolic by-products can result in health problems and change in the physical and chemical properties of their host environment. These biomaterials in some systems block the fluid transfer pipes and furthermore can cause chemical deterioration in such systems which results in poor performance and may require costly maintenance. An example is metal-working fluid emulsions or coolants in metal working machines where high microbial growth will cause instability, corrosion, odour and sludge formation resulting in undesirable performance by the fluid. The microbes growing in metalworking fluids could be aerobic bacteria such as Pseudomonas, Bacillus and Staphylococcus, Anaerobic Bacteria such as Desulfovibrio and fungus such as Penicillium spp. and Candid. 
Monitoring the microbial load in fluids will help in evaluation of the quality and efficiency of biocides used or the bio-stability of the materials in the fluid. There are different methods to determine the measure of microbial load such as plate count, direct microscopic count, ATP measurement and enzyme activity, which all are common methods in microbiology but are both time consuming and costly. The aforesaid methods will usually require a microbiologist or a person familiar with microbiological methods and also a laboratory setting. In many situations, having a user-friendly device for microbial evaluation in a short period of time on site and without having any knowledge of microbiology would be a great advantage.